In general, coffee is classified as raw bean coffee, raw bean ground coffee, and instant coffee. Since raw bean coffee is superior in taste and fragrance among them, 90% of the population drinking coffee in Europe are purchasing at a high price raw bean coffee which is roasted and sold by a package from a factory. Most families enjoying roasted bean coffee have a coffee grinder or mill. Roasting raw beans at home not only provides a fresh taste and fragrance but also is very economical in view of the price difference of 1:3 or 1:5 between raw beans and processed beans.
Also, vacuum-wrapped roasted bean coffee cannot be stored over 6 months after packaging at the factory, but the taste of coffee from roasting raw beans 1-2 years after being harvested is at its best because raw beans which are stored for a period of time mature well. Therefore, at this time a roaster is needed for home use which allows the storage of raw beans conveniently since sealing up raw beans for storage is not required, and which is able to roast at one time approximately 160 g raw beans which yields up to a maximum of 20 cups of coffee per day.
The prior roaster for roasting coffee beans with heated air was previously filed on Oct. 1, 1994 by the present applicant as U.S. Pat. No. 5,564,331. In such prior roaster, the quality of roasting depends on the generation of a whirlwind, but the whirlwind was not strong because it was generated at the bottom of the roasting vessel; the power consumption was as much as approximately 1300-1400 w; the fan was noisy because the motor had to be rotated at a speed as high as over about 11,000 rpm for generating the whirlwind; the apparatus was not easily hermetically sealed nor kept because the roasting vessel is composed of detachable glass; users are required to handle it with care; and there were difficulties in assembling, exporting, selling, packing, and transporting the apparatus due to a number of parts and the high production cost.